Cost–consequence analysis of a hemostatic matrix alone or in combination for spine surgery patients

Background: A five-year retrospective database analysis comparing the use of Floseal¹ flowable topical hemostat alone (F) and in combination with gelatin/thrombin (F?+?G/T) to achieve hemostasis and control surgical bleeding showed higher resource utilization for F?+?G/T cases relative to F matched pairs during spinal surgery. Lower resource use in the F group was characterized by shorter hospital length of stay and surgical time as well as fewer blood transfusions and less hemostat agent used per surgery.

Objective: To evaluate the cost–consequence of using F compared to F?+?G/T in minor, major and severe spinal surgery from the US hospital perspective.

Methods: A cost–consequence model was developed using the US hospital perspective. Model inputs include clinical inputs from the literature, cost inputs (hemostatic matrices, blood product transfusion, hospital stay and operating room time) from the literature, and an analysis of annual spine surgery volume (minor, major and severe) using the 2012 National Inpatient Sample (NIS) database. Costs are reported in 2017?US dollars. One-way and probabilistic sensitivity analyses address sources of variability in the results.

Results: A medium-volume hospital (130 spine surgeries per year) using F versus F?+?G/T for spine surgeries is expected to require 85 less hours of surgical time, 58 fewer hospital days and 7 fewer blood transfusions in addition to hemostat volume savings (F: 1?mL, thrombin: 1994?mL). The cost savings associated with the hospital resources for a medium-volume hospital are expected to be $317,959 (surgical hours?=?$154,746, hospital days?=?$125,237, blood transfusions?=?$19,023, hemostatic agents?=?$18,953) or $2445 per spine surgery.

Conclusions: The use of F versus F?+?G/T could lead to annual cost savings for US hospitals performing a low to high volume of spinal surgeries per year.     

集群企业技术能力构建的案例研究——基于能力矩阵

基于能力矩阵的分析框架,对集群企业的技术能力构建过程和基于OEM关系的超集群知识联系对该过程的影响进行了理论分析。以巴基斯坦的Sialkot集群和我国台湾地区的机床产业集群为案例对象,通过研究两集群中生产商的技术能力构建过程对相关命题进行检验。结论如下:集群企业的技术能力构建是一个多路径过程;基于OEM关系的超集群知识联系对集群企业技术能力构建的作用具有一定局限性;集群企业通过利用这类超集群知识联系开展富于进取心的、积极主动的学习,可以突破该局限性,克服价值链中领导企业设置的障碍,从而可以在更宽的功能范围内构建创新程度更高的技术能力。     

Strategic visualisation tools for managing technological information

In an information economy, the effective management of a massive amount of technological information is inevitable when attempting to facilitate the decision-making process. It is an important part of selecting R&D projects and allocating budgets to promising technology development. Information visualisation is thus regarded as a critical tool in technological information management because it can provide decisive implications that the intelligence of humans cannot produce. This paper proposes six graphical forms, including a technology tree, a technology map, a technology network, a technology matrix, a technology curve, and a technology dictionary, presenting the generic form and concept of each method. Moreover, the principles and applications of such visualisation tools are suggested in order to enhance their use in practical circumstances. A case study of TFT-LCD (thin film transistor-liquid crystal display) technology will help to explain how to apply visualisation tools to strategic technology management.     

一种基于自适应相似矩阵的谱聚类算法

为了消除在构建谱聚类算法的相似矩阵时,高斯核函数中尺度参数的波动影响,构建了一种自适应相似矩阵,并应用到谱聚类算法中。自适应相似矩阵中数据点间的距离度量采用测地距离算法,相距较近的两点间的距离近似于欧氏距离,相距较远的两点则先根据欧氏距离得到每个数据点的k个近邻点,然后累加近邻点的测地距离,由此得到每对数据点间的最短距离。两点间的局部密度用共享近邻的定义来表示,更好地刻画了数据集的本征结构。在5个人工数据集和国际通用UCI数据库中的5个真实数据集上进行实验。实验结果表明,所提算法的聚类准确率高于对比算法的准确率,对复杂分布数据有很强的自适应能力。研究成果为数据挖掘及机器学习提供了思路和方法。     

基于风险矩阵的风险投资项目风险评估

在对国内外风险投资项目风险评估方法进行分析的基础上,主要对风险矩阵方法在风险投资项目风险评估中的应用进行了探讨,构建了用于风险投资项目风险评估的风险矩阵,设计了利用风险矩阵进行风险评估的基本流程,以期为风险投资项目的风险评估提供一种科学、合理、简单易行的评估方法。     

Efficiency comparisons between two estimators based on matrix determinant Kantorovich-type inequalities

We first establish two matrix determinant Kantorovich-type inequalities. Then, based on these two and other inequalities, we introduce new efficiency criteria and present their upper bounds to make efficiency comparisons between the ordinary least squares estimator and the best linear unbiased estimator in the general linear model. We provide numerical examples to examine the upper bounds of some new and old efficiency criteria. Received: June 1999     

讨论矩阵的特征值与行列式的关系

利用矩阵的特征值解决行列式的问题。     

任意空间位置两多边形多匝线圈的互感计算

根据聂以曼公式推导出任意空间位置两多边形线圈互感的一般表达式,应用旋转矩阵实现了线圈位置的变化,通过MATLAB软件编程计算,绘出了互感的变化曲线,并对计算结果进行进行了分析验证。     

Practical Proposals for Specifying k-Nearest Neighbours Weights Matrices

Abstract

In this article, we introduce and evaluate testing procedures for specifying the number k of nearest neighbours in the weights matrix of a spatial econometric model. An increasing and a decreasing neighbours testing procedure are suggested. Kelejian's J-test for non-nested spatial models is used in the testing procedures. The testing procedures give formal justification for the choice of k, something which has been lacking in the classical spatial econometric literature. Simulations show that the testing procedures can be used in large samples to determine k. An empirical example involving house price data is provided.